1. Technical Field
The present invention relates to a method of manufacturing a light-emitting device, a light-emitting device, and a projector.
2. Related Art
In recent years, the development of semiconductor light-emitting elements has been energetically performed. As specific semiconductor light-emitting elements, a semiconductor laser (laser diode), a super luminescent diode (hereinafter also referred to as “SLD”), a light-emitting diode (LED), and the like have been known.
In light-emitting devices including such a semiconductor light-emitting element, the semiconductor light-emitting element is mounted on a support substrate such as a copper base for the purpose of efficiently dissipating the heat of the semiconductor light-emitting element (for example, refer to JP-A-2008-311371). In a light-emitting device disclosed in JP-A-2008-311371, a Cu substrate and a semiconductor light-emitting element are bonded via a bonding layer as a sintered body of Ag nanoparticles. It is considered that such a bonding layer can enhance thermal conductivity and thus the heat of the semiconductor light-emitting element can be efficiently conducted to the Cu substrate via the bonding layer.
The light-emitting device disclosed in JP-A-2008-311371 is manufactured as follows: a conductive paste is disposed on the Cu substrate; the conductive paste is subjected to a sintering process to form a first bonding layer; the first bonding layer and the semiconductor light-emitting element are bonded via a conductive paste; the conductive paste is subjected to a sintering process to form a second bonding layer; the Cu substrate and the semiconductor light-emitting element are bonded via a bonding layer formed of the first and second bonding layers. However, there is no suggestion about the state of the surface of the first bonding layer. In general, since relatively large irregularities are formed on the surface of the first bonding layer subjected only to a sintering process, voids (air bubbles) are likely to occur between the first bonding layer and the second bonding layer. The occurrence of voids reduces the heat transfer efficiency of the bonding layer, leading to a problem of reduced heat dissipation property.